1. Field of the Invention
The present invention generally relates to a pillow for head rest, particularly to an ergonomical pillow for head rest wherein the pillow can be used to stabilize movement of user's head and provide appropriate support to user according to his/her body type.
2. Description of Related Art
Humans spend on average one-third of his/her whole lives for sleeping. Researches have shown that sleep quality may take toll on our health, for an example demonstrating such discovery, sleep has been confirmed to be the best way to regain vitality, and sufficient amount of sleep is instrumental to youth's growth. Our brain continues to give instructions during our sleep time to different parts of our body for self-regeneration in order to sustain their normal functions. As well, our brain can also put together the information and knowledge we hear and learn during the day, and restructure them so as to formulate a memory block. In summary, sleep is an indispensable and essential component of our daily lives and health, and excellent sleep quality is instrumental to maintaining a good health.
Among other possible attributing factors to sleep quality, the pillow quality itself can be an important one. However, it is to be noted here that the Chinese proverbial saying that goes as “sleeping high on tall pillow keeps worry away” is actually a misleading conception. Under normal conditions, the human body is more adaptable to maintaining a natural posture where the vertebral column is kept in a straight line as looking from the front, but if viewed from a side perspective, the seven vertebrae of the cervical curve will appear in a curve in such a fashion to protrude forward. Therefore, the height of the pillow should also satisfy the arc length of such curve such that the cervical vertebrae can be maintained in a natural condition. Either a overshooting or low-pass pillow height can hardly keep the cervical vertebrae in a natural condition. This has been reported by users to be contributing to neck pain, or the so-called neck muscle spasm.
Medical experts have suggested that the pillow height for users lying with back on the floor to be kept between 5 to 8 cm as a best mode of practice. In another perspective, a majority of people cannot constantly remain in the same sleep posture while sleeping, for which the most common postures are lying on his/her back or on his/her side. As such, the most ideal pillow height, taking into consideration of each person's body type and shoulder width, gender, and age is between 8 to 10 cm. In another perspective, it is commonly known to best place the bottom edge of the pillow close to user's shoulder, and keep away from suspending the cervical vertebrae and back in mid-air. It will be understood to persons skilled in the art that such arrangement is sufficient to provide proper weight support and pressure relief.
Traditional pillows are known to be equal and symmetrical in terms of their shape, and the pillow surface used mainly for supporting user's head (particularly back of head) is a flat surface, and the majority of these traditional pillows tend not to be designed by ergonomical standards and without consideration of adapting to human body curves. Pillow surface highly suitable for back lying may appear to be slightly low for side lying. There has been proposed a memory pillow made from memory cotton, of which the central area is a flat surface, the edge of which has winding protrusions and is higher than the pillow surface such that the edge having protrusions can support weight of back of user's neck. However a disadvantage of the such design is suitable only for the back lying sleep posture because the protruding edge will become higher than the flat pillow surface in the middle, and such arrangement can cause the side of user's head (especially ears) to be turned to an inappropriate downward inclination posture.
U.S. Pat. No. 6,006,380 (hereinafter referred to as “cited reference”) discloses an adjustable cervical pillow with depression for a user's ear. The technical feature of the cited reference entails “an adjustable cervical pillow, with beautification properties, for supporting the head and neck of a person. The cervical pillow includes a resilient pillow body with a resilient upper portion that includes a plurality of depressions on a top face of the resilient upper portion for receiving a person's ear during use. The pillow body further includes a central depression and at least one head adjusting shim. The top face includes a raised cervical support region for supporting the neck of a user during use.” As those indicated in FIG. 3 and FIG. 4, the pillow is a solid-bodied pillow made from urethane foam, and the top head height adjustment includes raised cervical support region for supporting the base of the skull and neck. As a result, the pillow can support the weight of the user's head by way of the pillow's overall support capacity. However, this design will not work to deliver a shock-absorbing functionality, because it can only provide a structural support to the user's neck. Moreover, the pillow is solid-bodied, as such it is not equipped with a space designed for allowing air ventilation, and therefore it is not capable of distributing heat. The cited reference is designed to only support the user's neck by way of adjusting the height of the user's neck, but cannot offer other benefits including pressure distribution, shock absorbance, and air-ventilation-mediated heat distribution.